The present invention relates generally to the field of flow control valves and the construction thereof. More specifically, the present invention relates to the internal components of valves including a reinforced elastomer seat that provides a sealing surface for the valve components.
Flow control valves such as, for example, knife gate valves or line blind valves, are used to control the flow of process media and can be particularly well suited for use with abrasive and corrosive slurries used in, for example, the mining, pulp or paper industries. One form of gate valve known in the art includes a housing constructed of two halves that when coupled together form the valve housing and passageway therethrough. On opposite sides of the housing are connections for installing the valve in a pipe line, for example, the housing can be bolted to a flange end of a pipe. To control the flow of fluid through the valve, the valve includes a knife gate that is disposed within a valve body which is comprised of two valve body halves. In operation, when the knife gate is raised, the valve is open and process media flows through the passageway. When the knife gate is lowered, the valve is closed and process media is prevented from flowing through the passageway.
Each of the valve body halves includes a recess in which is disposed a valve seat that provides a sealing function between the knife gate and the valve body. The valve seat seals against the gate when the gate is in the open configuration to allow for process media to flow through the valve while substantially preventing process leakage out of the valve housing. Previous valve seats include a top horizontal portion which is displaced within the valve body when the gate valve is lowered or raised. This movement with the recesses of the valve body causes process media to leak into the valve housing. One previous valve seat included one or more injection chambers within the horizontal portion of the valve seat. These chambers were accessible from outside the valve housing and adapted to receive injectable packing which created a seal with the knife gate. However, use of injectable packing did not provide a rigid enough valve seat to prevent displacement within the recesses of the valve body. Thus, there is a need for a knife gate valve seat configured to prevent displacement within a valve housing when the valve is opened and closed.